Point detector



Nov. 25 a 1924- C. S. BUSHNELL POINT DETECTOR Filed Nov. 1, 1920 5 sheetsh d 1 C. S. BUSHNELL POINT DETECTOR 1, 1920 3 Sheets-Sheet 2 Filed Nov m *T FT'I Fla. 2.

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Nov. 25, 1924i 1,517,236

C. S. BUSHNELL POINT DETECTOR Filed Nov. 1, 1920 3 Sheets-Sheet 5 Patented Nov. 25,

CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASSIGNOR T GENERAL RAIL- WAY SIGNAL COMPANY, OF GATES, NEW YORK, A CO'RPORATION OF NEW YORK.

roiiv'r nnrnctron.

To all whom it may concern:

Be it known that 1, CHARLES S. BUSH- NELL, citizen of the United States, residing at Rochester, in the county of Monroe and State. of NeivYork, have invented certain new and useful improvements in Point Detectors, of which the following is a specification.

This invention relates to circuit controlling devices, commonly called point detectors, which are used in connection with switches in interlocking systems for railroads for the purpose of safe-guarding the movementof trains over such switches. The point detector is associated with the switch machine, or switch and lock-movement, operating the switch-points, and is directly connected to said switch points, so that the operation of the point detector is dependent upon the position of the switch points and the locking and unlocking operation of the switch machine. The point detector governs directly or indirectly the circuits of the signals governing traiiic over this switch, and acts to signal trains to stop if the switch points are not in their proper position or are not properly locked.

It is desirable that such a point detector, like all devices used. in railway signaling systems, should be guarded as far as possible against dangerous failure from any cause. in one type of switch machine and point detector, to which the present invention is more particularly applicable, the normal or reverse positions of the point detector (corresponding to the normal and reverse position of the switch point) are not selected by the switch machine but are dependent solely upon the connections between the point detector and the switch. points. With such an arrangement it may happen that the point detector will falsely assume one position, althoi'igh the switch points are in the opposite position, in case all the connections to the switch points are broken, or accidentally disconnected.

The primary object of the present invention is to obviate the possibility of a false failure as outlined above; and in a specific embodiment of the invention this is accomplished by making the operation of the point detector dependent upon the movement of the lock rod of the switch machine. Other objects of the invention will appear hereinafter as the characteristic features of 1, 1920. Serial No. 421,009.

the construction, functions and mode of operation of my improved point detector are described in detail.

In describing the invention 1 will refer to the accompanying drawings, in which- 'Figure l is a diagrammatic view, partly in perspective and with some parts broken away or spread apart for clearness, which shows the principal operating parts of a switch. machine of well known construction having my improved point detector applied thereto;

Fig. 2 is a plan view of the point detector, with some parts broken away;

Fig. 3 is a vertical transverse section through the point detector on the line 33 in Fig. 2;

Fig. 4 is a similar transverse section on the line 4-4 in Fig. 2; and

Fig. 5 is a diagrammatic view illustrating the more significant parts of the point detector, together with its connection to the points of a single slip switch, these parts being selected and arranged to facilitate explanation of the construction and operation of the point detector.

1 have illustrated my improved point detector in connection with a switch machine similar to that shown and described, for example, in the patent to W. K. Howe, No. 1,288,595, dated December 24s, 1918; but it should be understood that the invention may be used in connection with the other specific constructions of switch machines, by male ing appropriate changes in mechanical details.

Referring to Fig. l, the stock rails of a conventional switch are designated 1, and themovable switch points 2. These switch points 2 are connected to a throw bar T and a lock rod LR of the switch machine, these parts being shown separated and to different scales for convenience and clearness. The switch machine is operated by an electric motor M of any suitable type, which is shown as a series wound direct current motor having an armature 3 and a field 4. The armature shaft of the motor M drives a main gear 5 journaled by a fixed stud 6 through suitable reduction gearing. This reduction gearing, as shown, comprises a bevel pinion 7 meshing with a bevel gear 8 which drives a shaft 9 through a friction clutch 10 (shown enclosed) a pinion 11 on said shaft 9 meshing with a gear 12 on a second shaft 13; and a pinion 14 on said second-shaft meshing with'the main gear 5. The main gear is rotated in one direction or the other toreversethe switch points by changing the direction ofl'rotationmotor armature. Fa'st'ened eccentrically to the main. gear which carries two freely revoluble rollers 16 and 17 at its lower end. :Thisdrivirig pin is moved by the main gear 5 111 acircular path-indicatedby-the dotand'dash line '18.

"The upper roller 16 cooperates with the edges of a laterally opening jaw or cam 19 inthe throw rod '1, and actslto reciprocate said throw bar as the-main gear 5 is rotated first in one direction and then in the other. Extending lengthwise of the switchqmachine is alocki'ng plunger LP whichiis guided at one endby a block 20 and at other points in its length by suitable lugs (not shown). This locking plunger LP is provided'with an enlarged head 21 in which is formed-a cam-slotf22-of a. general ellipticalshape, the lower roller 17 being disposed to cooperate withthe edges of this cam slot and reciprocate sa-idlocking plunger as the -main gear 5 isrotated. The locking plunger LP carries a lock dog arranged to engtigebehind shouldersQri-fi on the throwbar T; and another lock dog'25 fastened to said locking plunger is arranged mentor-normal and-reversenotches (not shown) in the'lock rodLld thereby holdingthe throwbar and -the lock rod against movement and'locking the switch points. Inthepresent invention, the lock dog 25 is formed with alongitudinal groove with flared or beveled ends, as best shown 1n Fig. 5, soas to cooperate with the po nt detector as hereinafter explained.

l h loclgrod L3 is shown as madeup of two bars, which inpracticeare made relatively adjustable by suitable -1neans (not shown) for thepurpose explained-in the prior patent above mentioned.

The circuit controller for governing the operat on of the switch machine comprises in general-two units or groups of contacts and their operating means, designated as a whole O and P, one for controlling-the operating andindication circuits (hereinafter termed the operating circuit controller),-and the other for controlling the circuitsofthe pole changer coils (hereinaftertermed the pole changer coilcontroller). Each unit comprisesa plurality of-fixed contact springs or fingers, asQQarr-anged'in rows along opposite sides of the machine and carried by su1tcontactstrips, as 32 adaptedto bridge pairs 0 is a downwardly extending driving pin 15 of the contact springs 26. The contact car--- rier 28 of the-operating circuit controller 0 is supported by the cores 33 of the normal and reverse pole changer coils 34: and 35, and is shifftciil baclr'nnd lorth an arm 36 loosely mounted on a vertical shaft 37 and having-a jaw straddling a pin 38 connected to said contact carrier. Thus, contact carrier-'28 may-be shifted electrically by the pole changer coils 34 and 35, or mechanically by a contact shifter designated as a whole The contactblock 29 of the pole changer coil controller P is operatively connected to'thecontact shifter CSby a pin 39 and a jaw 40 integral with said contact shifter.

The contact shifter CS is an irregular shaped piece comprising a bottom plate d1, carrying normalandreverse operating rollers 4-2- 42 anda centeringroller 43 a top portion 54k; and two upright side bars 45%5 The centeringroller i3 cooperates with'two parallel guide strips 46 fastened t'othe locking plunger 'LP and having their ends beveled in such a way that when the locking plunger is moved to its unlocked position (tothe right as shown) these guide strips 46 cooperate with the roller 45 and. move contact shifter-GS to the middle position and hold it there until the locking plunger is returned .to its locked position.

:The contact shifter CS is shifted to its extreme positions by normal and reverse sclecting plungers ll-4J which are carried in brackets 48-48 fastened to opposite bars of the lock rod LR. These selecting plungers LT-L7 are arranged to be projected by thejlock dog 2-5 against the roller 42 or 4-2 as the switch machine locks up.

lVhen the contact shifter CS is moved to its middle position, the contact carrier 29 is likewise moved to its middle positiom but on account of the space between arm 30 and eachfof the sidebars 45, contact carrier 28 is not moved. l/Vhen the contact shifter GS is operated to its. extreme position however, both of the contact carriers 28 and 29 are shilited to the correspomhng extreme position.

the parts in Fig. 1) and as the driving pin 15 is moved in its circular path 18, the lower roller 17 engages one edge of the cam slot 22and shifts the locklng plunger Ll (to the right as shown) to its unlocked position, thereby unlocking the throw bar 'l and'thc lock rodLR The guide strips -16 put the contact shifter CS to the middle po sition. This in turn places the contact car- Ill) rier 29 in its middle position, bridging both sets of contact fingers 26 associated therewith, so that the circuit through either the normal or reverse pole-changer coils 341- or 35 may be set up, thereby enabling the machine to be reversed in mid-stroke if desired, in a manner characteristic of this system and fully explained in the prior patent above mentioned. As the driving pin continues its movement, the upper roller 16 engages the jaw 19 of the throw bar T and shifts said throw bar to the other extreme position. The lower roller 17 now engages the other edge of the cam slot 22 and returns the locking plunger LP to its locked position. During the movement of the switch points, the lock rod LR is shifted from the position shown to the other position, on ac count of the movement of the switch points, and this places the selecting plunger 17 opposite the roller 42 so that when the lock dog returns to the position shown in Fig. 1, it carries with it said selecting plunger 47 and causes the contact shifter CS to be swung to its other extreme position. This movement shifts the operating circuit controller 0, thereby breaking the motor operating circuit and setting up the indication circuit. The motor M new acts as a generator, in the manner characteristic of this dynamic indication system, and the generated current is transmitted to the tower through the indication magnet of the lever corresponding to the switch in question, with the result that this lever is released and the operator is thus informed that the desired movement of the switch has been accomplished. The operation of unlocking and moving the switch points back to their former position is similar to that described.

In connection with this type of switch mas chine it will be noted that the locking plunger LP is moved out (to the right) and then back to the same position during the cycle of operation of moving the switch points from one position to the other. This kind of locking, conveniently called out and in locking, does not allow the position of the point detector to be selected by the locking plunger, so that my improved point detector is particularly applicable to switch machines having this type of locking.

It will also be noted that the look rod LR constitutes an essential element in the cycle of operation. If this look rod LR is removed from the machine, the contact shifter is not operated from its middle position; and if th connection between this look rod and the switch points is broken, the contact shifter CS will not be properly shifted to the other position, but will merely be returned to its former position, with the result that current is not cut oil from the operating motor nor the correct indication circuit established. In short, the presence and proper operation of that lock rod Lit is essential to the proper .perforniiance of the switch machine, and its absence or failure to move will be immediately detected.

Referring now to the construction of my improved point detector, 1 have shown my invention in connection with a specific type of point detector which comprises a plurality of detecting bars D, which are connected in any suitable way, as shown, for example in Fi 5, to each point, or to each pair of points, of a switch, or movable point frog, as the case may be. These bars D extend transversely of the switch machine, and are guided at the sides thereof by the frame or casing of said machine.

The operating parts of the point detector are disposed above the detecting bars D and are supported from a suitable frame work or casing. The circuit controlling element of the point detector, which I have termed a contact cradle G, comprises two side memhere 50, which are disposed vertically, and are connected at their tops by a horizontal flat bar 51, and at the bottom by an operating lug or foot 52, having one end beveled, as best shown in Fig. 5. To the top bar 51 is fastened a block 53 of suitable insulating material which has embedded therewith a number of metallic contact pieces 54. A plurality of resilient contact fingers 55 are fastened at their ends to blocks 56 of suitable insulating material which extend parallel with the top bar 51 and are suitably fastened, as by screws, to the frame work or casing of the device. When the contact cradle C is in one extreme position, as shown in Fig. 4, its contact pieces 54 electrically connect the several pairs of contact fingers 55 on that side; when said cradle is swung to a neutral or middle position, the contact fingers on both sides are disconnected; and when said cradle is swung to the other extreme position, the several fingers 55 on that side are electri cally connected. lln this way suitable controlling circuits may be selectively made and broken in accordance with the position of the switch points, and these circuits may be used to control directly, or indirectly, the signals governing traffic over the switch in question.

The contact cradle C is supported by a rocker yoke Y so as to be able to rock on a horizontal axis about a point near its middle, and also move bodily up and down to a limited extent. This rocker yoke Y co1nprises two side arms 57 connected at their middle by a transverse web 58. These side arms 57 carry at one end a horizontal pin 59 which passes through the side members 50 of the contact cradle (l and constitutes its rocking support, said pin 59 being held in place by small transverse pins or the like. The side arms 57 are pivotally supported at their upper ends by a pin 60 which is supported in downwardly extending lugs of a horizontal top plate 61. Between the eb V and R,

i To ,one v ide meinher 01 the ,eontact cradle v(3 1s iesi n a inverted i -shel ed i y okel65,the ends of which overlie the pro.-

v jecting ends ,ofthe bre lzets BffSPonthe lock rod LR, so {filial} with the 1991; rod in one position, as shown in Fig. 4,.one oiisoid brackets l8is under one endoftheyokefifi,

The gdetecting hers ,1) pass under the rollersN and Band aloovethe foot 52, of the contact eradle- Q, es shown in Fig. i l fiend these bars are providedwith narrow grooves or -notches 66 in their upper feces, ,rvhich A have rounded ,endsnnd are slightly I'llhe length and arrangehel th r ll r nent ofthe notohes 66 is slightly .diilerent according I to the use to which .the point detectoris put, ,and one errengement suitable f a s ngl slip :swii l i ust ated i rig- "The operation of the point detector feen he more readily nnderstood .f join ,consideration. of its simplest application toiesingle vslip switch which has heen shownidiegnenin aticallyin-Fig. 5. Tyvo- ,detec ting hers Q and-D are used, these hers being connected y red {and 6. espe tive y, t sw ch lugs of the tyyo switch pointsQ. Th sdetect- .1 9; 1 1 1 D i Pr i withe hort notch 6.6?which con es underneath one of therollers of the normal setN, when the switch points. ere the. normalv position .as shown This: .loarl) elso hes alonger: notch (fi errenged to. some underneath 1e. roller t in the ene e w en h w tch P int e moved to. the vreverse position. The detectin-g bZI.I.D is similarly provided with a short notohfl fifi rand a long notc hufifihztrmi -see ee Ro le o th r m i ner me se n h c rre pon i g resia i oithe switch points. It will benotedtl at a short notch 66*. in. one detecting; leer is ,op

gposite-the long notchfio in the other dete'ctring bar. This arrangement ,of long and "short notehes is provided so thetthe two .de-

testing bars may he applied to, switches herinigwdifferent n ove1nents. .or throws, without changing the notohing.

lit-l1 the switch points in the, norniel position-end locked, ns sliowntin Fig. .5, the

' ,ngprmel notches. 6,6. 6,6" of: the, ,b are;

end D are ,under vthe normal rollers N.

1 the -.locking plunger .is :in the l d d Posi ion, the: eek dqe2 is @eeeee i ,eimee fee 52 mg seem-Q radl 0- Thesp ine ;62 t ds dwmo e the pi 59, an s nseql e tl t e conta crri 1$ Wh l downward; and .e result said ei'edlo lioeksto the nornntl or left lizbnd position as shown, fulcrun ing about the point where th re e s r llers R be r P the PD-$ e ses h d t et ng b rs- Ll/Vhen thesWitc-lr inachineis operated the flared ends oi the groove in the lock dog -2 5engz ge the foot 52 of theconteet cradle C end force itto its middle position by e wcdgingtoreaina n. Contact erec ile 'i m-e nte ned i this mid e 9 ne tra ps i t-i with a ircu ts J rdo 0 12; th

tc m i e i unlo ked- ,As the switch points are thrown, the lock 10 L i shifted the e y .(F th f a shown) it m its eo malnesit o t temsverse position, end the extension on -the re ke e81 i e i'te to om ilndc th P- .iteet omdle-meyis ing r m the middl p ition to itsreverseposition (to the right us shown) whut ,QfilIDQtSWlQg hack to its normal .pes o' he detect g ber n D 'elsb move withth Wl h poi11tS, .$9 th t h 1 v.e1;se notches therein come under the reyerseset of rollers 11. When the locking iqlimei h -been in r d to ts leek pesi- .ti -n; ==Q1 1b ere le ,1 th n .f to a ume its eise p s ion, lwcv n lie a i n the vSpring, in the same ay nspiteviously expla e Fr m t f e ing i e b s t e? th .movements.,o ftheeontect cradle C z 1re, de- .nendent uponthelocking plunger LP,,the ,position of the detecting bars noting c101- lectively, endfinally .uppnthe p ositionuof th lock e When he swit h T m chine unlocked, the cont,e ct pliadle is held in its dd r.-.1 :e p i h -l k 1Qe2 rIf he-d te t n b y- D an D do .ee fhot movie, then their notches do not line 1p end allow the rollersto drop in. Further, the

v coo-peretion of the yoke, with the, Joreclgets '4;8.48 presents vthe .coiitactqc f idle C gas sign n iuq itti n out o eoi'resu ndenc with the pos t on of tlielock rod. In this neted in such eweyns to check .eaclrpther. To illustrate the important feature of the present invention, assume that the connections between all ,of the dectecting burs, as

D ,and D ,erebnolgen, or that'the main- 7 4 8 enggtges the yoke 65 and preyents such noveinent of the contact cradle. The yoke fifidoes not touch the bneckets 48 4 8 except when something happens to prevent movement of all of the detecting bars. In short, the yoke '65 together withthe'brackets 4- l8fl constitutes a safety check upon the position of the contact cradle C. In this connection it should be understood that the dangerous condition obviated by the yoke will exist only in case all of the detecting bars fail to move. If only one bar fails to move, then the contact cradle C is held in its middle position, since the notches for neither set of rollers are all lined up. it should also be remembered that the lock rod LR cannot be removed from the machine, or fail to move when the switch points are thrown, without immediate detection at the next operation of the switch machine. My improved point detector, therefore fully protected against any false failure.

My improved point detector, like others of this type, detects abnormal or improper movement of either one of a pair of switch points, since all the detecting bars must bein a corresponding position to allow the rollers to drop into the notches. If one of the switch points is displaced while the switch machine, is not operating, the bar connected to that point will force up the roller in its notch and shift the contact cradle G to its neutral position. When such roller is in a short notch, the contact cradle C is put in its neutral position by very slight movement .of the corresponding detecting bar; and the arrangement of notches in rollore is such that, when the switch point to which a given detecting bar is connected becomes the closed point of the switch, then the short notch of this detecting bar is under one of the sets of rollers. The open point. of a switch may move to a considerable extent in practice without causing appreciable danger to train movement, and consequently a long notch which facilitates the adjustment of the device for switches of different throws, affords all the desired protection. The short notches in the detecting bars may of course, be used for both the open and closed switch points; but it is preferred to use an arrangement of short and long notches to provide the. requisite adjustment for variation in the throw of the points of dilferent switches, or even the same switch. i r

The particular construction illustrated has a capacity of four detecting bars, as shown in Fig. 2; and this provides for the detecting of all four points separately of a double slip switch or a movable point frog. When the detection of only two switch points, or of four switch points in pairs, is desired, either two detecting bars alone may be employed, or four detecting bars coupled together in pairs. Also the detecting bars may beconnected with the switch machine on either side of the switch. These,

and other adaptations and modifications of the structure. of the point detector, are disclosed and claimed in the application of R. C. Leaks, 283,369, filed March 18, 1919, the present invention being in the nature of an improvement in the type of point de-' tector disclosed in said Leake application.

I have shown and described one specific embodiment of my invention and in the form I have devised for use with a point detector and a switch machine of one particular construction, but I desire to have it understood that the construction and arrangement of parts illustrated is susceptible of various changes and modifications in practice without departing from the invention.

What I claim as new and desire to secure by Letters Patent of the United States, is

1; In operating mechanism for switch points of the type which comprises a lock rod and a point detector comprising detecting bars, said lock rod and detecting bars being connected to'the switch points, a circuit controlling element movable from a neutral position to either of two extreme posi tions and having its extreme position selected in accordance with the position of the detecting bars acting collectively, and engageable members 011 said circuit controlling element and said lock rod cooperating to prevent a movement of said circuit controlling element to an extreme position unless the lock rod is in a corresponding position.

2. A point detector for switch machines having a lock rod and a locking plunger for locking said lock rod, comprising a plurality of detecting bars, and circuitcontrolling means governed by the detecting bars and the locking plunger and also having its position dependent upon the position of the lock rod. v

3. A point detector for switch machines having lock rods connected to switch points,

comprising a plurality of detecting bars, a three-position circuit controller governed by said bars, and engageable members on said circuitv controller and the lock rod for preventing movement of said circuit controller out of correspondence with the position of said lock rod.

' 4. In a device for governing switch points, a horizontally 'movablelock rod coupled to the switch points, a plurality of detecting bars also connected to said switch points, a three-position circuit con trolling element mounted to rock about a. horizontal axis, and cooperating means on the lock rod and said element to prevent movement of said element to one extreme position or the other unless the lock rod is in a corresponding position.

5. A oint detector of the type in which a pluraity of detecting bars govern the 0perati'Qn 61 21" Circuit co'iit fo'l l ingeieinfit, the Combination with said element, of other means conn'eted to the sWithpointS for detefr'nining' the position of saidjeienint.

6, A point detector for electrically ape-r: ite'd switch" ln'ziehinee of the type in which thefoperating of indi'czitio'n cifeuits for the 7 machine are controlled by a; lock rod conn'eetefi' to" the; switch points, which said ljo'ek'ro'd is held in it's xamineposi eons y a locking plunger, omppismge an element preventing movement of s itiot ei erod, locking plunger and detecting bars actting separately and individually.

16. A point detector for switch machines having a reciprocable locking plunger for locking the switch points in both positions, a plurality of detecting hers connected to the switch points, circuit controlling means governed by said detecting bars and actuated to a neutral position by the unlocking movement of said plnngen and other means connected to the switch points for independently determining the position or" said circuit controlling means.

17. In a device oil the character described, the combination With a three-position contact element. a lock rod, a locking plunger and a plurality oii detecting bars, said lock rod, locking plunger and detecting bars acting separately and independently to deter.- mine the position of said contact element.

18. A point detector of the type described comprising, a spring pressed rockingcircuit controlling element, a lock rod, connected to the switch points, and engageable members on the lock rod and said element for preventing movement of the element to either extreme position unless the lock rod is in a corresponding position.

19 In a combined point detector and switch operating mechanism, a lock rod, a plurality of detecting bars, a locking plunger movable transversely to said lock rod and detecting bars, and circuit controlling means adjacent the point of intersection of saidplunger, lock rod and detecting bars and separately actuated thereby.

In testimony whereof I have affixed my signature.

CHARLES S. BUSHNELL. 

